/***
 * 代码题第三题。基于下面提供的代码，完成后续的四个练习
 */
class Container{
    static of(value){
        return new Container(value)
    }
    constructor(value){
        this._value = value;
    }
    map(fn){
        return Container.of(fn(this._value));
    }
}

class Maybe {
    static of(x){
        return new Maybe(x);
    }
    isNothing(){
        return this._value === null || this._value === undefined;
    }
    constructor(value){
        this._value = value;
    }
    map(fn){
        return this.isNothing() ? this : Maybe.of(fn(this._value));
    }
}
module.exports = {Maybe, Container}
 